Miter limit only applies to angles IN the path, not its ends. Cap style applies to ends, but Inkscape does not offer a 'tapered' cap style.You probably want to change the shape profile for best results.

- rect3420.png (4.44 KiB) Viewed 2709 times
The included profiles may work for you, but you can make any profile and copy it to the clipboard to use it, as I have done here.(The top path is the profile)

- rect3407.png (4.75 KiB) Viewed 2709 times
Note that this changes the simple bezier path to a path with a path effect applied, so you need to know what you are eventually going to do with the SVG to decide whether to convert it to a simple path before saving...
Your mind is what you think it is.